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I am researcher in high-energy astroparticle physics and Feodor Lynen Research fellow of the Humboldt foundation at Stanford University and the Kavli Insitute of Particle Astrophysics and Cosmology (KIPAC).

I am the coordinator of the Dark Matter & New Physics working group of the Fermi-LAT (Large Area Telescope) Collaboration and an associated member of the H.E.S.S. (High Energy Stereoscopic System) Collaboration. I am also a member of the the CTA (Cherenkov Telescope Array) Consortium.

Before joining KIPAC I was a post-doc at the Oskar Klein Centre at Stockholm University in Jan Conrad's group.

Originally, I am from Hamburg, Germany, where I also did my PhD in Prof. Dieter Horns' group.


Below I summarize some of my research interests within gamma-ray astronomy.

  1. INDIRECT DARK MATTER SEARCHES - More than 80% of all matter in the Unverse is made up of enigmatic dark matter that does neither absorb or emit any radiation. We know that it exists due to its gravitational interactions but its exact nature remains one of the fundamental problems of physics today. One possibility is that Dark Matter is composed of a (or several) yet undiscovered fundamental particle.  My research uses gamma-ray observations to search for two dark matter particle candidates, so called axions and axionlike particles (ALPs) as well as weakly interacting massive particles (WIMPs). Check out this NASA news article for some more information. 
  2. COSMIC ACCELERATORS - In order to produce high-energy photons (gamma rays, ~ 1 million times more energetic than X-rays), extreme environments are necessary that accelerate particles beyond energies reachable with particle colliders such as the LHC at CERN in Switzerland. I study two types of such environments: blazar jets and supernova remnants, in particular the Crab nebula. Blazars are special type of galaxies that produce outflows of particles that travel almost at the speed of light. In these jets gamma rays are produced and if we look right down the jet, they appear very bright and we can see these blazars even if they are billions of light years away.
    Supernova remnants like the Crab nebula, on the other hand, are the remains of an exploded star. In the case of the Crab, there is a fast-rotating neutron star in the center. Particles are thought to be accelerated on shock fronts in the ejecta of the progenitor. 
  3. PROPAGATION OF HIGH ENERGY PHOTONS IN THE UNIVERSE - gamma rays do not traverse the Universe unperturbed. They can interact with background radiation such as the extragalactic background light (EBL). The EBL consists of the starlight emitted over the entire history of the Universe and the starlight that has been absorbed and re-emitted by dust. If a gamma-ray interacts with an EBL photon, it produces a pair of one electron and its anti-particle, the positron. Just like clouds block the sunlight, the EBL can partially block gamma rays from reaching us. Using a certain type of galaxies, so called blazars, as cosmic beacons of gamma rays, we can study the EBL and eventually the formation of stars during the history of the Universe. Much more about the EBL will be learned with future CTA observations. Check out the article "What the Propagation of Energetic Light Can tell us About the Evolution of Stars, Intergalactic Magnetic Fields and Fundamental Physics" in the CTA newsletter for further information.  
  4. INTERGALACTIC MAGNETIC FIELDS - The electron-positron pair discussed above can again scatter photons of the cosmic microwave background, boosting them to gamma-ray energies. These gamma rays can again interact with the EBL and create a chain reaction of produced electrons and positrons and gamma rays. Since electrons and positrons are charged, they are deflected by magnetic fields. If the intergalactic magnetic field (IGMF) is sufficiently strong, the gamma rays in the cascade arrive delayed from the primary gamma rays and blazars would appear extended in the gamma-ray sky. I use observations of the Fermi-LAT satellite and imaging Cherenkov Telescopes to search for such features, and I have derived projections for CTA to look for the cascade gamma rays. 


Please find below some data files connected to my research. If you use these files, please cite the appropriate papers: NGC 1275 analysis, ALP induced gamma-ray burst, CTA sensitivity for ALP detection, ALP lower limits for transparency hint, 2015 Crab nebula model, 2010 Crab model


You can find my publication list and links to bibliography services below. 

18 publications in peer-reviewed journals with major contribution (8 as corresponding author), and 2 articles submitted for publication. Co-author of 38 publications of the H.E.S.S. collaboration, 9 publications of the Fermi-LAT collaboration, 21 conference proceedings, and 1 white paper. The publications have in total more than 1600 citations with an h index of 20. 


An incomplete list of seminars and presentations.


- "Indirect Axion and Axionlike Particle Searches at Gamma-Ray Energies", Invited talk at the 7th International Fermi Symposium, 15-20 October, Garmisch-Partenkirchen, Germany
-"Searches for Angular Extension in High Latitude Fermi-LAT Sources" and "AMEGO: Dark Matter Prospects", talks at the TeV Particle Astrophysics 2017 (TeVPA 2017) Conference, 7-11 August, Columbus, OH, USA, see also this video
- "Astrophysical searches for axions and axionlike particles at gammaray energies", Invited talk at the South American Dark Matter Workshop, May 10-12, ICTP-SAIFR, São Paulo, Brazil
- Invited Seminar at the Universidad Católica de Chile (April 17) and Universidad de Santiago de Chile, April 18
"Future Constraints of Dark Matter Effective Field Theories and Simplified Models with CTA", DM@LHC workshop, April 3-5 UC Irvine, California, USA
- Invited talk at the GRAPPA Seminar, January 23, Gravitation and Astroparticle Physics in Amsterdam center, University of Amsterdam, Netherlands


- Invited talk at the Astroparticle Seminar at the Niels Bohr International Academy, November 1, Niels Bohr Institute, University of Copenhagen
- Invited talk at Fysikdagarna (Physics Days) Conference, 27-29 October, Gothemborg, Sweden
- Talk at the TeV Particle Astrophysics 2016 (TeVPA 2016) Conference, 12-16 September, CERN, Geneva, Switzerland
- Invited talk at the 12th Patras Workshop on Axions, WIMPs, and WISPs, 20-24 June, 2016, Jeju Island, South Korea
- Invited talk at the Workshop on Perspectives on the Extragalactic Frontier: from Astrophysics to Fundamental Physics, 2-4 May, ICTP, Trieste, Italy 


- "Search for Axion-like Particle Signatures in Gamma-ray Data". Given at the Gamma Rays and Dark Matter Workshop, 7-12 Decenmber, 2016, Obergurgl, Austria.
- "Search for axion-like particles signatures in the gamma-ray spectrum of NGC 1275". Talk at the Partikeldagarna, 30 November - 1December, Uppsala, Sweden
- "Search for Axion-like Particle Signatures in the Gamma-Ray Spectrum of NGC 1275" for the Fermi-LAT collaboration. Plenary talk at the Sixth International Fermi Symposium, 9-13 November, 2015, Washington DC, USA. 
- "Search for axion-like particle signatures in the gamma-ray spectrum of NGC 1275". Talk at the 11th Patras Workshop on Axions, WIMPs, and WISPs, 22-26 June, 2015, Zaragoza, Spain.


- Talk "Sensitivity of H.E.S.S. II and the Cherenkov Telescope Array to detect photon-axion-like particle oscillations in different magnetic fields at high gamma-ray opacities" at the 10th PATRAS Workshop on Axions, WIMPs and WISPs, 29 June - 4 July, CERN, Geneva, Switzerland
- "Sensitivity of H.E.S.S. II and CTA to detect a reduced ɣ-ray opacity due to photon-axion- like-particle oscillations". Invited talk at the "Gamma-ray Constraints on the EBL and the IGMF" Meeting-in-a-Meeting at the 224th AAS Meeting, 1-5 June, 2014, Boston, MA, USA.
- Sensitivity of the Cherenkov Telescope Array to the Detection of Axion-like Particles". Invited talk at the SLAC Gamma-ray Blazar Workshop, 12-13 March, 2014, Stanford, CA, USA.
- "Search for Axion-like particle signatures in gamma-ray spectra". Talk at the UCLA Dark Matter 2014 Conference, 26-28 February, 2014, Los Angeles, CA, USA.


- "Opacity of the Universe for VHE gamma-rays in the presence of axion-like particles". Invited talk at the workshop "What are we learning from the gamma-ray sky?", 10-12 October, 2013, Minneapolis, MN, USA
- "Impact of axion-like particles on observations with IACTs". Talk at the 2013 European Physical Society Conference on High Energy Physics, 18-24 June, 2013, Stockholm, Sweden.

© Copyright Manuel Meyer 2018.  Last update: May 7, 2018